Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/02—Cosmetics or similar toiletry preparations characterised by special physical form
  • A61K8/04—Dispersions; Emulsions
  • A61K8/042—Gels
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/02—Cosmetics or similar toiletry preparations characterised by special physical form
  • A61K8/04—Dispersions; Emulsions
  • A61K8/06—Emulsions
  • A61K8/064—Water-in-oil emulsions, e.g. Water-in-silicone emulsions
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
  • A61K8/72—Cosmetics or similar toiletry preparations characterised by the composition containing organic macromolecular compounds
  • A61K8/81—Cosmetics or similar toiletry preparations characterised by the composition containing organic macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
  • A61K8/8141—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
  • A61K8/8158—Homopolymers or copolymers of amides or imides, e.g. (meth) acrylamide; Compositions of derivatives of such polymers
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61Q—SPECIFIC USE OF COSMETICS OR SIMILAR TOILETRY PREPARATIONS
  • A61Q17/00—Barrier preparations; Preparations brought into direct contact with the skin for affording protection against external influences, e.g. sunlight, X-rays or other harmful rays, corrosive materials, bacteria or insect stings
  • A61Q17/04—Topical preparations for affording protection against sunlight or other radiation; Topical sun tanning preparations

Definitions

• the subject of the present invention is emulsions of water in oil type, with a high content of aqueous phase, their preparation process and their uses.
• the emulsions make it possible to convey both water-soluble and liposoluble substances and therefore find application in particular in the cosmetic, pharmaceutical and veterinary fields, and in the field of detergents.
• Emulsions which provide a feeling of freshness and which are felt when applied to the skin as not "sticky" are particularly sought after.
• Emulsions are classified according to the nature of the continuous phase (also called “external phase”), in which droplets of the other phase (known as “internal phase”) are dispersed.
• oil in water O / W
• the emulsion is of the "water in oil” (W / O) type.
• US Pat. No. 5,746,945 describes water-in-oil type emulsions which are stabilized by an emulsifying system having two components: a) a polyalkyl polyether polysiloxane copolymer and b) a derivative of phthalic anhydride (a monoamide).
• the method for preparing emulsions in this document consists of the gradual addition of the aqueous phase to the oily phase.
• the two phases are each independently of the other heated to 160 to 165 ° F (71 to 74 ° C) before being combined to obtain the emulsion.
• Document WO-97/40814 describes W / O emulsions intended in particular to be used for impregnating baby wipes.
• the organic phase of the emulsions necessarily contains a wax.
• the emulsifiers used are of the carboxylic acid type, substituted by hydrocarbons, or "block" copolymers. dBA, involving monomers such as 12-hydroxystearic acid and ethylene glycol, or an alkyldimethicone copolyol.
• the fatty phase and the aqueous phase are typically heated to 160 ° F (71 ° C) and then mixed at this temperature to obtain the emulsion.
• a problem to be solved therefore consists in providing W / O emulsions with a high content of aqueous phase, which in particular have a fresh and non-sticky texture.
• the present application relates to cosmetic, pharmaceutical, veterinary or detergent preparations containing an emulsion as defined above.
• the water-in-oil emulsion generally comprises from 2 to 40% by weight, preferably from 2 to 20% by weight, of oil (s).
• the fatty phase is prepared in the presence of an emulsifying system of lipophilic nature, comprising one or more emulsifying surfactants.
• lipoamino acids and their salts lipopeptides and their salts
• sorbitan esters such as, for example, the product sold under the name MONTANE® 80 by the company SEPPIC
• polyglycerol esters such as for example the products sold under the name ISOLAN® GI34 by BASF and PLUROL® DIISOSTEARIQUE by GATTEFOSSE
• ethoxylated castor oil and ethoxylated hydrogenated castor oil for example the product sold under the name SIMULSOL® 989 by the company SEPPIC
• glycerol stearate polyglycol or polyglycerol polyhydroxystearates
• Nonionic and anionic silicone emulsifying surfactants are also capable of being used in the context of the present invention, even if for practical reasons (they can cause a modification of the sensory properties of the emulsions obtained), they do not represent an aspect preferred of the invention.
• emulsifying surfactants of the alkylpolyglycoside type for example those described in patent application FR-A-2 790 977, in particular xylose derivatives.
• the mixture of alkylpolyglycosides consisting of the reaction products of a saccharide and a dimerdiol having 36 carbon atoms is in fact composed of a mixture in all proportions of hydroxyalkylpolyglycosides (products resulting from the acetalization of one of the two hydroxyl groups of dimerdiol) and of polyglycosylalkylpolyglycosides (products resulting from the acetalization of the two hydroxyl groups of dimerdiol).
• dimeric acid is a dibasic acid having 36 carbon atoms, the majority compound of which can be represented by the formula:
• alkyl polyglycosides may contain, as the saccharide residue, a residue of glucose or dextrose, fructose, galactose, mannose, ribose, xylose, preferably a residue of glucose or xylose.
• each unit of the polysaccharide part of the abovementioned alkyl polyglycosides can be in anomeric form ⁇ or ⁇ , and the rest of the saccharide can be of the furanoside or pyranoside type.
• the average degree of polymerization of each saccharide residue is generally between 1.05 and 2.5, more preferably between 1.1 and 2.
• alkylpolyglycoside used in the context of the present application therefore denotes either an alkylmonooside (degree of polymerization equal to 1) or an alkylpolyglycoside (degree of polymerization greater than 1).
• the dimerdiol used for the preparation of the above emulsifying surfactant is a diol obtained from the hydrogenation of dimer acid.
• This compound due to its origin, may contain minor proportions of impurities.
• impurities can be present in amounts of up to 30% by weight of the total weight of the diol.
• the emulsifying surfactants based on alkylpolyglycosides and fatty diols can comprise, in corresponding minor proportions, such impurities, or the reaction products of these impurities with a saccharide.
• the emulsifying surfactants based on alkylpolyglycosides and fatty diols which can be used in the context of the present invention can be prepared by simple mixing of their constituents in desired predetermined proportions.
• alkylpolyglycosides On an industrial scale, they will preferably be prepared according to one of the two routes conventionally used for the synthesis of alkylpolyglycosides, and for example by reaction, in acid medium, between dimerdiol and a saccharide having an anomeric OH, such than glucose or dextrose.
• this synthesis may be supplemented by operations of neutralization, filtration, distillation or partial extraction of excess fatty diol or discoloration.
• an emulsifying system which contains at least one emulsifying surfactant chosen from alkylpolyglycosides, alkylpolyglycoside (s) and fatty alcohol (s) compositions, polyol esters (such as polyglycols and polyglycerols and possibly other polyols) optionally alkoxylated such as polyhydroxystearates of polyols (such as polyglycols or polyglycerols) optionally alkoxylated, polyethylene glycol-alkyl glycol copolymers.
• emulsifying surfactant chosen from alkylpolyglycosides, alkylpolyglycoside (s) and fatty alcohol (s) compositions, polyol esters (such as polyglycols and polyglycerols and possibly other polyols) optionally alkoxylated such as polyhydroxystearates of polyols (such as polyglycols or polyglycerols) optionally al
• an emulsifier system containing an optionally alkoxylated polyglycerol ester such as a polyglycerol polyhydroxystearate), an optionally alkoxylated polyglycol polyhydroxystearate, or a polyethylene glycol-alkylglycol copolymer, in combination with an alkylpolyglycoside or a composition, is used.
• the water-in-oil emulsion generally comprises up to 10% by weight, preferably up to 5% by weight, and even more preferably from 0.5 to 5% by weight of the emulsifying system comprising one or more emulsifying surfactants .
• the phrase “partially or totally salified” means that the strong acid or weak acid functions are partially or totally salified in the form in particular of the alkali metal salt, such as the sodium salt or the potassium salt, of the salt ammonium or amino alcohol salt, such as for example, the monoethanolamine salt.
• the strong acid function of the monomer can in particular be the sulfonic acid function or the phosphonic acid function, said functions being partially or totally salified.
• Said monomer will advantageously be chosen from styrene sulfonic acid or 2-sulfoethyl methacrylate, styrene phosphonic acid, partially or fully salified, 2-methyl acid - [(1-oxo-2-propenyl) amino] 1-propane sulfonic acid (AMPS) partially or totally salified in the form of sodium salt, ammonium salt or monoethanolamine salt.
• APMS 2-methyl acid - [(1-oxo-2-propenyl) amino] 1-propane sulfonic acid
• the weak acid function of the monomer can in particular be the partially or fully salified carboxylic acid function.
• Said monomer can in particular be chosen from acrylic acid, methacrylic acid, itaconic acid or maleic acid partially or totally salified in the form of the sodium salt, potassium salt, ammonium salt or salt monoethanolamine.
• the polymer is a copolymer based on a monomer having a strong acid function partially or totally salified, copolymerized, with at least one neutral monomer
• said neutral monomer is in particular chosen from acrylamide, methacrylamide, vinylpyrrolidone, (2-hydroxyethyl) acrylate, (2,3-dihydroxypropyl) acrylate, (2-hydroxyethyl) methacrylate or (2,3-dihydroxypropyl) methacrylate or an ethoxylated derivative of molecular weight between 400 and 1000, of each of these hydroxylated esters, the tris (hydroxymethyl) -acrylamidomethane or the tris (hydroxymethyl) methacrylamidomethane or an ethoxylated derivative of molecular weight between 400 and 1500, of each of these amides.
• aqueous phase of the emulsions according to the present invention comprises a polyelectrolyte whose ionic sites are associated with their counterions contributes to the fact that the complementary supply of mineral salts is not necessary.
• branched polymer is meant a non-linear polymer which has pendant chains so as to obtain, when this polymer is dissolved in water, a strong state of entanglement leading to viscosities at low gradient very important.
• crosslinked polymer is meant a non-linear polymer in the state of a three-dimensional network insoluble in water, but swellable with water and therefore leading to the production of a chemical gel.
• the crosslinking agent and / or the branching agent is chosen in particular from diethylenic, polyethylenic compounds, and very particularly from diallyloxyacetic acid or a salt thereof and in particular its salt sodium, triallylamine, trimethylol propanetriacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diallylurea or methylene bis (acrylamide).
• the crosslinking and / or branching agent is generally used in the molar proportion expressed relative to the monomers used, from 0.005% to 1%, in particular from 0.01% to 0.2% and more particularly from 0, 01% to 0.1%.
• polyelectrolyte type polymers which are suitable for producing emulsions according to the present invention are therefore copolymers or homopolymers, which may or may not be crosslinked or branched, comprising monomers having a strong or weak acid function partially or totally salified, or a cationic function.
• polymers of polyelectrolyte type which are particularly suitable for carrying out the process of the present invention
• derivatives of acrylamide, acrylic acid and vinylpyrrolidone such as copolymers of acrylic acid and 2-methyl acid - [(1-oxo-2-propenyl) amino] 1-propane sulfonic acid (AMPS), the copolymers of acrylamide and 2-methyl acid - [(1- oxo-2-propenyl) amino] 1-propane sulfonic, copolymers of 2-methyl acid - [(1-oxo-2-propenyl) amino] 1-propane sulfonic and (2-hydroxyethyl acrylate) ), homopolymer of 2-methyl acid - [(1-oxo-2-propenyl) amino] 1-propane sulfonic acid, homopolymer of acrylic acid, copolymers of acryloyl ethyl trimethyl ammonium chloride and acrylamide
• Such polymers are generally prepared by a reverse phase polymerization process, and are in particular marketed respectively under the names SIMULGEL® EG, SEPIGEL® 305, SIMULGEL® NS, SIMULGEL® 800 and SIMULGEL® A by the company SEPPIC. They involve forms partially or fully salified acid monomers. The corresponding monomer (s) is (are) dissolved in drops of water dispersed in a fatty phase using a surfactant. In this type of polymerization, each drop of water in the water-in-oil emulsion constitutes in itself a "small reactor". This system minimizes the likelihood of termination reactions and leads to higher molecular weight polymer chains. At the end of the reaction, a hydrophilic surfactant and water are added. The polymer deploys, no longer being constrained by the size of the drop of water in which it was synthesized, leading to a "soft solid", characterized by a three-dimensional structure.
• This preparation process uses surfactants, such as sorbitan esters, mannitan esters, polyhydroxystearates of polyglycols, polyglycerols or polyols, alkanolamides on linear or branched fatty chains, ethoxylated sorbitan esters, esters ethoxylated mannitan, ethoxylated nonylphenols, ethoxylated octylphenols. Therefore, the surfactants mentioned above may be present in the gelled aqueous phase during the implementation of the method of the invention.
• surfactants such as sorbitan esters, mannitan esters, polyhydroxystearates of polyglycols, polyglycerols or polyols, alkanolamides on linear or branched fatty chains, ethoxylated sorbitan esters, esters ethoxylated mannitan, ethoxylated nonylphenols, ethoxylated
• the dry weight of said polyelectrolyte constitutes between 0.1% and 4% and preferably between 0.5% and 2% of the weight of the aqueous phase, if the process for preparing such a polyelectrolyte results from a polymerization process precipitating; or the dry weight of said polyelectrolyte constitutes between 0.25% and 4% and preferably between 0.5% and 2% of the weight of the aqueous phase if the process for the preparation of such a polyelectrolyte results from a process for the preparation of reverse emulsion polymerization.
• the polyelectrolyte type polymers used in the process of the present invention have a shear thinning behavior (non-Newtonian), that is to say that the viscosity observed varies as a function of the shear gradient.
• the polyelectrolyte type polymers which can be used in the context of the present invention exhibit non-Newtonian rheological behavior in solution, characterized by a gradient index of between 0.1 and 0.7, and preferably between 0.2 and 0, 5.
• the gelled aqueous phase obtained by dissolving the polyelectrolyte type polymer will have a viscosity of between 0.5 and 300 Pa.s, preferably between 1.0 and 150 Pa.s and more particularly between 5 and 100 Pa.s , measured on a BROOKFIELD LV viscometer (6 rpm, 20 ° C).
• the water-in-oil emulsion according to the present invention can also optionally contain up to 10% by weight of a stabilizer.
• stabilizing agents capable of being used in the context of the present invention, mention may be made of hydrogenated castor oil; stearic acid and its metal salts such as aluminum stearate; hydrophobic silicas; polymers such as the products sold under the name KRATON® POLYMERS by the company KRATON; clays such as hectorite or bentonite; hydrophobic modified starches, for example the product sold under the name DRY FLO PC® by the company NATIONAL STARCH; crosslinked or non-crosslinked polymethylmethacrylates such as MICROPEARL marketed by the company SEPPIC, polyamides such as Orgasol 2002 marketed by the company ATOCHEM.
• KRATON® POLYMERS by the company KRATON
• clays such as hectorite or bentonite
• hydrophobic modified starches for example the product sold under the name DRY FLO PC® by the company NATIONAL STARCH
• crosslinked or non-crosslinked polymethylmethacrylates such as MICROP
• Waxes of vegetable, animal or mineral origin such as beeswax, carnauba wax, candellila wax or ozokerite, are also capable of being used in the context of the present invention, even if for practical reasons, they do not represent a preferred aspect of the invention.
• these emulsions may further comprise one or more compounds chosen from humectants, such as for example glycerin, glycols, the sodium salt of 5-carboxylic acid of 2-pyrrolidone, preservatives such as for example the products known under the name SEPICIDE® and marketed by the company SEPPIC, dyes, perfumes, cosmetic active agents such as for example vitamins and derivatives of water-soluble vitamins, vitamins and derivatives of fat-soluble vitamins, oligosaccharides , proteins, polypeptides, amino acids, N-acylated derivatives of amino acids and / or polypeptides and / or proteins, plant extracts, seaweed extracts, mineral or organic sunscreens, mineral fillers such as mica, silica and talc, synthetic fillers such as nylons and poly (methyl methacrylate) crosslinked or not, sil elastomers icon, sericite.
• humectants such as for example glycerin, glycols, the sodium salt of 5-carboxylic
• the water-in-oil emulsion can also comprise one or more electrolyte mineral salts, such as for example magnesium chloride, magnesium sulfate, sodium borate or sodium chloride, in an amount ranging from 0.1% to 5% by weight. These electrolytes are however not essential for obtaining the emulsions according to the invention.
• These compounds can be introduced into the aqueous phase or into the oily phase, depending on their affinity for these phases.
• the emulsions according to the invention are obtained by adding the fatty phase to the aqueous phase. It is possible to operate at temperatures up to 80 ° C. However, it is advantageous to minimize the energy expenditure represented by the heating of the phases and it is therefore preferable to produce the emulsion at a temperature below 55 ° C. Even more preferably, the fatty phase will be added to the gelled aqueous phase at a temperature between 20 ° C and 35 ° C, that is to say at room temperature.
• the emulsion according to the invention can be produced by mixing the two phases at a stirring speed exceeding 1500 revolutions per minute. It is advantageous, however, to minimize the energy expended in the agitation used to produce the emulsion. We therefore prefer a stirring speed less than 1000 revolutions per minute, and we particularly prefer a stirring speed between 80 and 800 revolutions per minute. Even more preferably, a stirring speed of between 80 and 450 rpm will be chosen, very particularly between 80 and 330 rpm.
• the emulsions according to the invention which are stable over time, advantageously have a polydispersity index greater than 41%, preferably greater than 45% and more preferably greater than or equal to 51%.
• the polydispersity is determined by particle size analysis on a diluted form of the emulsion using a laser granulometer of the MALVERN MASTERSIZER type.
• the order of adding the phases is reversed with respect to the usual order of preparation of a water in oil type emulsion (W / O).
• Adding the fatty phase to the aqueous phase represents a gain in productivity in itself. Indeed, the fatty phase is of a smaller volume than the aqueous phase, which can allow the use of a single preparation tank, and has a much lower viscosity.
• the W / O emulsion according to the invention can be advantageously used in a cosmetic, dermocosmetic, pharmaceutical or veterinary preparation.
• the W / O emulsion according to the invention can also be used in a detergent preparation.
• the W / O emulsion according to the invention is a solar emulsion, in which one or more sun filters (substances making it possible to prevent ultraviolet radiation from reaching the skin of the user) is (are) incorporated in the fatty phase and / or in the gelled aqueous phase.
• the water resistance of oil-in-water emulsions is however low. It may therefore be necessary to add additives which "structure” or “stiffen” the aqueous phase, such as poly (vinylpyrrolidone), polyacrylates, polyacrylamides or even silicone oils which increase the water-repellent properties of the film. obtained by spreading the emulsion.
• additives which "structure” or “stiffen” the aqueous phase, such as poly (vinylpyrrolidone), polyacrylates, polyacrylamides or even silicone oils which increase the water-repellent properties of the film. obtained by spreading the emulsion.
• oils previously mentioned for the preparation of solar emulsions according to the present invention. It is preferred however for this application to use one or more synthetic oils, chosen from the group consisting of fatty acid esters such as isodecyl neopentanoate, butyl myristate, propyl myristate, cetyl myristate, palmitate d isopropyl, 2-ethylhexyl palmitate, butyl stearate, hexadecyl stearate, isopropyl stearate, octyl stearate, isoketyl stearate, dodecyl oleate, hexyl laurate, propylene glycol dicaprylate, esters derived from lanolic acid, such as isopropyl lanolate, isocetyl lanolate, monoglycerides, diglycerides and triglycerides of fatty acids such as
• the solar emulsions according to the present invention comprise a photoprotective system comprising one or more solar filters, which can be incorporated in the fatty phase and / or in the gelled aqueous phase.
• the solar emulsions comprise approximately 2% to approximately 40% by weight, preferably approximately 5% to approximately 20% by weight of solar filter (s).
• the gelled aqueous phase of the emulsion comprises (s) sunscreen (s), this (these) is (are) generally directly dispersed in the gelled aqueous phase if it ( s) is (are) liquid (s) or, if (s) is (are) solid (s), it (s) is (are) generally previously dispersed (s) in a solvent such as ethanol or in another liquid sunscreen which dissolves it before being incorporated into the aqueous gel.
• sunscreen sunscreen
• Sunscreens can be organic or inorganic in nature, and it is possible to combine organic and inorganic filters in one sunscreen emulsion.
• benzoic acid derivatives such as para-aminobenzoic acids (PABA), in particular the monoglycerol esters of PABA, the ethyl esters of N, N-propoxy PABA, the ethyl esters of N, N-diethoxy PABA, ethyl esters of N, N-dimethyl PABA, methyl esters of N, N-dimethyl PABA, butyl esters of N, N-dimethyl PABA; the family of anthranilic acid derivatives such as homomenthyl-N-acetyl anthranilate; the family of salicylic acid derivatives such as amyl salicylate, homomenthyl salicylate, ethylhexyl salicylate, phenyl salicylate, benzyl salicylate, p-isopropanolphenyl salicylate; the family of cinnamic acid derivatives such as ethylhe
• mineral screens also called “mineral screens"
• titanium oxides zinc oxides, cerium oxide, zirconium oxide, yellow, red or black iron oxides, oxides of chrome.
• These mineral screens can be micronized or not, have undergone or not surface treatments and may be presented in the form of aqueous or oily pre-dispersions.
• solar emulsions according to the present invention comprise one or more mineral fillers in the oily phase.
• Fat phase Alkyl polyxylosides on Isofol® 20 prepared according to EP1142901 1.6% PEG45 dodecylglycol copolymer (ELFACOS® ST9) 0.4% Triglyceride C8-C10 8.0% Aqueous phase Water qs 100% Glycerin 5% SIMULGEL® EG 2%
• the fatty phase is heated moderately (50 ° C max.) Until the mixture of the three constituents is clear. This fatty phase can be stored at room temperature for several days without causing crystallization of the various surfactants present.
• aqueous gel comprising water, a water-soluble polymer presented in reverse emulsion under the trade name Simulgel® EG, and the glycerin is prepared at room temperature with conventional stirring for this type of preparation (RAYNERI deflocculator), at a temperature of 18 -25 ° C, with a stirring speed of 300 rpm.
• the fatty phase is added all at once to the gel, at room temperature and at a moderate stirring speed (200 to 300 revolutions / min.) With an agitator equipped with an anchor-type mobile. This stirring is then maintained for ten minutes and no cooling step is necessary.
• the emulsion obtained is a water-in-oil emulsion which, due to its high water content, has a strong shear-thinning character associated with a non-sticky and fresh feel.
• Example 2 The same procedure as that described in Example 1 is used in an 8 kg pilot reactor, equipped with a planetary mixer.
• the emulsification speed with such a system was 100 revolutions / min and the maintenance phase, after the end of the addition of the fatty phase, lasted thirty minutes.
• Example 1 The conditions of Example 1 were reproduced using an agitator of the rotor stator type, operating at a speed of 4000 revolutions / minute, to produce the emulsion.
• the fatty phase is heated to 80 ° C. until the mixture of the three constituents is clear.
• aqueous gel comprising water, a water-soluble polymer presented in reverse emulsion under the trade name Simulgel® EG, and the glycerin is prepared at room temperature with conventional stirring for this type of preparation (RAYNERI deflocculator). It is then heated to 80 ° C.
• the fatty phase is added all at once to the gel, and the stirring conditions of Example 3 were reproduced.
• Example 1 Example 2
• Example 3 Example 4 Quantity manufactured 200g 8kg 200g 200g Emulsification temperature 20-25 ° C 20-25 ° C 20-25 ° C 80 ° C Stirring speed during emulsification 300 rpm 100 rpm 4,000 rpm 4,000 rpm Characteristics of the emulsion obtained / SENS (1) E / H E / H E / H E / H VISCOSITY (2) 55.6 Pa.s 58.0 Pa.s 51.2 Pa.s 51.2 Pa.s (1) method: 1g of emulsion is diluted in 5g of demineralized water. If the emulsion is immiscible with water, it is W / O. (2) method: BROOKFIELD LV 6rpm (at 20 ° C)
• Example 3 shows that the direction of the W / O emulsion and the order of magnitude of the viscosity of the emulsion obtained are similar regardless of the amount of energy supplied to the system. .
• the viscosity measurements are carried out at 20 ° C.
• the gradient indices, shown in Table 2, are obtained by calculating the convexity of the curve analyzed according to the mathematical model of the power law.
• the gradient index is generally less than 0.5 for gels based on polyelectrolyte polymers.
• the polydispersity of the water-in-oil emulsion obtained was measured according to the method indicated above (particle size analysis on a dilute form of the emulsion using a laser granulometer of the MALVERN MASTERSIZER type).
• the polydispersity index of the emulsion was greater than 51%. Furthermore, the gradient index of the aqueous phase of this water-in-oil emulsion was 0.28.
• Fat phase Alkyl polyxylosides on Isofol® 20 prepared according to EP1142901 2.4% PEG45 dodecylglycol copolymer (ELFACOS® ST9) 0.6% Triglyceride C8-C10 12.0% Aqueous phase Water qs 100% SIMULGEL® EG x%
• Example 1 The conditions of Example 1 were reproduced using an anchor-type agitator, operating at a speed of 300 revolutions / minute, to produce the emulsion.
• the DEM expressed in milliljoules, corresponds to the smallest light energy resulting in a perceptible and homogeneous erythema, with clear contours.
• Colorimetric measurements are first carried out on the sites to be irradiated using a device such as the MINOLTA Chromameter®. Indeed, the type of skin must be determined, because the result of the test is very dependent on the color of the subject's skin.
• Skin types are divided into six categories, type 1 corresponding to the whitest skin encountered, which burns after exposure to the sun and which does not tan at all.
• Type 6 corresponds to the darkest skin tones, people with this phototype (generally of African origin) having skin that (almost) never burns.
• subjects of phototypes II and III are chosen which are the most representative of the phototypes subject to a significant increase in erythema by ultraviolet radiation.
• the affected areas are irradiated using a Xenon lamp following a geometric progression of 1.25, according to the supposed index of the product and the reference .
• the Xenon lamp can for example be an IDEM 3000® Arquantiel short arc lamp, irradiating on a spectrum ranging from 290 to 400 nm.
• Infrared radiation is filtered using a UG11 type filter (1 mm), and the elimination of IR is also carried out using a water filter and ventilation.
• the irradiation surface is at least 1 cm 2 .
• the transmitter power is around 1000 W.
• the unprotected Minimum Erythemal Dose (DEMnp) and the DEMs protected by the reference and by the product are read simultaneously.
• the persistence of a solar product is studied by UV irradiation after a water resistance test. This test consists in taking the volunteers two baths at 30 ⁇ 2 ° C for 20 minutes with a ten-minute break between each bath ("standardized bath"). The first bath is taken 15 minutes after applying the solar composition to be tested.
• a solar emulsion having the composition indicated in Table 4 was prepared according to the method described in Example 1 above, the solar filters being incorporated in the fatty phase.
• the photoprotection index and the percentage of persistence with respect to water were determined according to the protocols mentioned in the previous section. Subsequently, the sensory evaluation was carried out through a panel of experts.
• Example 8 combines water resistance performance with great ease of spreading, a non-greasy feel and an absence of tacky effect, with a similar photoprotection index. to that of Comparative Example 3, which reflects knowledge of the state of the art for producing water-in-oil emulsions stabilized by the presence of microcrystalline waxes and not implementing the method according to the present invention.
• the solar emulsion is this time made with the following components: 1. MONTANOV® WO18 1 1.5% 2. PEG45 dodecyl glycol copolymer 0.8% 3. Diisopropyl adipate 10% 4. TINOSORB M (50% ai) 2 20% 5. Ethylhexyl methoxycinnamate 5% 6. SEPIGEL® 305 2% 7. Water qs 100% 8. Additives: preservatives, perfume, citric acid qs 1 Isostearyl glucoside and isostearyl alcohol 2 Dispersion containing 50% active ingredient
• Ingredients 1 to 3 are mixed and brought to 50 ° C until clear.
• the other ingredients of the fatty phase 4 + 5 are added. Separately we form a gel with 6 + 7.
• the fatty phase is added to the gel.
• IP30 solar emulsion which has a water resistance index of 72%.
• This emulsion is light, non-greasy, non-sticky and very easy to spread. It has an amount of 15% oil; it is also obtained by a process that does not require significant energy input.
• Example Comparative example 4 Example 10 Nature of the product obtained O / W cream gel W / O emulsion with gelled aqueous phase Emulsifying system PEG30 dipolyhydroxystearate - 0.4 Fluidanov® 20X - 1.6 Fat phase Di isopropyl adipate 12% 12% Filter system Ethylhexyl salicylate 5% 5% Ethylhexylméthoxycinnamate 5% 5% Ethyl hexyldimethyl p- 8% 8% aminobenzoate butylmethoxydibenzoylmethane 2% 2% Polymer SIMULGEL® NS 3% 3% Other additives Glycerin 1.5% 1.5% preservatives qs qs Water qs 100% Stability stable Stable Photoprotection index 15 +/- 3 25 +/- 3 % water resistance 18% + / - 10 60% + / - 10 Sensory evaluation Ease of spreading 10 9 Fat feeling 2 2 Sticky
• Example 10 The procedure of Example 10 and Comparative Example 4 is repeated, but with an oily phase of different structure and a filtering system of mineral nature.
• Table 6 Example Comparative example 5
• Example 11 Nature of the product obtained O / W cream gel W / O emulsion with gelled aqueous phase Emulsifying system PEG30 dipolyhydroxystearate - 0.6% Fluidanov® 20X - 2.4% Fat phase Caprylic capric triglyceride 12% 12% Filter system Titanium dioxide uv titan m160 10% 10% Polymer SIMULGEL® EG 2.1% 2.1% Other additives Glycerin 1.5% 1.5% preservatives qs qs Water qs 100% Stability granular Stable Photoprotection index - 21 +/- 3 % water resistance - 51% + / - 10 Sensory evaluation - Ease of spreading 7 Fat feeling 3 Sticky effect 1
• the method according to the invention makes it possible to incorporate a mineral filtering system with a gelling step of the aqueous phase, in order to achieve a water-in-oil emulsion, while stabilization proves impossible after gelling of the aqueous phase. , in the oil-in-water scheme, without a surfactant system as in the present invention.

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